Chamber conditioning and removal processes

ABSTRACT

Exemplary methods for conditioning a processing region of a semiconductor processing chamber may include forming conditioning plasma effluents of an oxygen-containing precursor in a semiconductor processing chamber. The methods may include contacting interior surfaces of the semiconductor processing chamber bordering a substrate processing region with the conditioning plasma effluents. The methods may also include treating the interior surfaces of the semiconductor processing chamber.

TECHNICAL FIELD

The present technology relates to semiconductor processes and equipment.More specifically, the present technology relates to etching materialssubsequent a chamber conditioning process.

BACKGROUND

Integrated circuits are made possible by processes which produceintricately patterned material layers on substrate surfaces. Producingpatterned material on a substrate requires controlled methods forremoval of exposed material. Chemical etching is used for a variety ofpurposes including transferring a pattern in photoresist into underlyinglayers, thinning layers, or thinning lateral dimensions of featuresalready present on the surface. Often it is desirable to have an etchprocess that etches one material faster than another facilitating, forexample, a pattern transfer process. Such an etch process is said to beselective to the first material. As a result of the diversity ofmaterials, circuits, and processes, etch processes have been developedwith a selectivity towards a variety of materials.

Etch processes may be termed wet or dry based on the materials used inthe process. A wet HF etch preferentially removes silicon oxide overother dielectrics and materials. However, wet processes may havedifficulty penetrating some constrained trenches and also may sometimesdeform the remaining material. Dry etches produced in local plasmasformed within the substrate processing region can penetrate moreconstrained trenches and exhibit less deformation of delicate remainingstructures. However, local plasmas may damage the substrate through theproduction of electric arcs as they discharge. Additionally, plasmaeffluents may impact subsequent processing of additional substrates.

Thus, there is a need for improved systems and methods that can be usedto produce high quality devices and structures. These and other needsare addressed by the present technology.

SUMMARY

Exemplary methods for conditioning a processing region of asemiconductor processing chamber may include forming conditioning plasmaeffluents of an oxygen-containing precursor in a semiconductorprocessing chamber. The methods may include contacting interior surfacesof the semiconductor processing chamber bordering a substrate processingregion with the conditioning plasma effluents. The methods may alsoinclude treating the interior surfaces of the semiconductor processingchamber

In some embodiments, the methods may also include transferring asubstrate into the substrate processing region subsequent the operationof treating the interior surfaces with the conditioning plasmaeffluents. The substrate may include an exposed region of titaniumnitride. The methods may include flowing a fluorine-containing precursorinto a remote plasma region fluidly coupled with the substrateprocessing region while forming a remote plasma in the remote plasmaregion to produce etching plasma effluents. The methods may includeetching the exposed region of titanium nitride by flowing the etchingplasma effluents into the substrate processing region through aperturesin a showerhead. The showerhead may be disposed between the remoteplasma region and the substrate processing region. The substrate mayfurther include an exposed region of tungsten, and the etching mayremove titanium nitride at a selectivity relative to tungsten of greaterthan or about 100:1. An amount of titanium nitride at an edge region ofthe substrate and an amount of titanium nitride at a central region ofthe substrate may be etched to within about 5% of one another.

The methods may also include flowing a hydrogen-containing precursorwith the fluorine-containing precursor to produce the etching plasmaeffluents. The hydrogen-containing precursor may be hydrogen or ammonia.The methods may also include flowing an oxygen-containing precursor withthe fluorine-containing precursor to produce the etching plasmaeffluents. A temperature of the substrate may be maintained betweenabout 200° C. and about 500° C. during the etching. The substrateprocessing region may be essentially devoid of hydrogen during theoperation of treating the interior surfaces of the semiconductorprocessing chamber with the conditioning plasma effluents. Theconditioning plasma effluents may be produced locally in the substrateprocessing region of the semiconductor processing chamber. Theconditioning plasma effluents may also be produced in a remote plasmaregion and may be flowed from the remote plasma region into thesubstrate processing region. A plasma power used to produce theconditioning plasma effluents may be less than or about 500 W. Thesubstrate processing region may be defined from above by a showerhead,and a pedestal within the substrate processing region may be maintainedwithin about 5 cm of the showerhead during the treating.

The present technology may also encompass methods including formingconditioning plasma effluents of a fluorine-containing precursor and anoxygen-containing precursor in a semiconductor processing chamber. Themethods may include contacting interior surfaces of the semiconductorprocessing chamber bordering a substrate processing region with theconditioning plasma effluents. The methods may also include treating theinterior surfaces of the semiconductor processing chamber.

In some embodiments, the methods may also include transferring asubstrate into the substrate processing region subsequent the operationof treating the interior surfaces with the conditioning plasmaeffluents. The substrate may include an exposed region of titaniumnitride. The methods may include flowing a fluorine-containing precursorinto a remote plasma region fluidly coupled with the substrateprocessing region while forming a remote plasma in the remote plasmaregion to produce etching plasma effluents. The methods may also includeetching the exposed region of titanium nitride by flowing the etchingplasma effluents into the substrate processing region through aperturesin a showerhead. The showerhead may be disposed between the remoteplasma region and the substrate processing region. A pressure within thesemiconductor processing chamber may be maintained between about 1 Torrand about 10 Torr. A temperature of the substrate may be maintainedbetween about 200° C. and about 500° C.

The present technology may also encompass methods including formingconditioning plasma effluents of a fluorine-containing precursor and anoxygen-containing precursor in a semiconductor processing chamber. Themethods may include contacting interior surfaces of the semiconductorprocessing chamber bordering a substrate processing region with theconditioning plasma effluents. The methods may include treating theinterior surfaces of the semiconductor processing chamber. The methodsmay include transferring a substrate into the substrate processingregion, and the substrate may include an exposed region of titaniumnitride. The methods may also include flowing a fluorine-containingprecursor into the substrate processing region. The methods may alsoinclude etching the exposed region of titanium nitride by contacting theexposed region of titanium nitride with the fluorine-containingprecursor. A temperature of the substrate may be maintained betweenabout 200° C. and about 500° C. during the etching. An amount oftitanium nitride at an edge region of the substrate and an amount oftitanium nitride at a central region of the substrate may be etched towithin about 5% of one another.

Such technology may provide numerous benefits over conventional systemsand techniques. For example, the etching methods may remove titaniumnitride selectively relative to numerous other materials. Additionally,the process may provide uniformity of the etch process and stability ofthe process between substrates. These and other embodiments, along withmany of their advantages and features, are described in more detail inconjunction with the below description and attached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the disclosedtechnology may be realized by reference to the remaining portions of thespecification and the drawings.

FIG. 1 shows a top plan view of one embodiment of an exemplaryprocessing system according to embodiments of the present technology.

FIG. 2A shows a schematic cross-sectional view of an exemplaryprocessing chamber according to embodiments of the present technology.

FIG. 2B shows a detailed view of a portion of the processing chamberillustrated in FIG. 2A according to embodiments of the presenttechnology.

FIG. 3 shows a bottom plan view of an exemplary showerhead according toembodiments of the present technology.

FIG. 4 shows exemplary operations in a method according to embodimentsof the present technology.

Several of the figures are included as schematics. It is to beunderstood that the figures are for illustrative purposes, and are notto be considered of scale unless specifically stated to be of scale.Additionally, as schematics, the figures are provided to aidcomprehension and may not include all aspects or information compared torealistic representations, and may include exaggerated material forillustrative purposes.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a letter thatdistinguishes among the similar components. If only the first referencelabel is used in the specification, the description is applicable to anyone of the similar components having the same first reference labelirrespective of the letter.

DETAILED DESCRIPTION

As semiconductor device features continue to reduce in size, improvingselectivity and uniformity of etch processes becomes increasinglyimportant. Etch processes performed to remove a variety of materials mayproduce byproducts either from etched materials, or from the precursorsused as the etchant. Although conventional technologies utilize pumpsand other flow characteristics to remove these materials from thesemiconductor processing chamber, some materials may adhere to chamberwalls and may remain during subsequent substrate processing. Forexample, etch processes utilizing fluorine-containing precursors mayproduce multiple reactants including fluorine radical species duringplasma processing. Fluorine radicals may adhere to chamber sidewalls orinterior surfaces. When a subsequent etch process is performed on thenext substrate in a batch, these retained fluorine radicals may impactthe etch process, and may affect uniformity of the etch along edgeregions of the substrate that may be nearer to the chamber sidewalls.

The present technology overcomes these issues by performing a chamberconditioning process that may be performed before an etch process isbegun, and may be performed between each successive etch process. Theconditioning or treatment operations may facilitate removal of residualeffluents or materials within the chamber. This may increase not onlythe uniformity of each etch process performed, but may also improve thestability of the process from substrate-to-substrate. By flowing anoxygen-containing precursor during the treatment, residual fluorineradicals or species adhering to chamber sidewalls may be oxidized andremoved from the chamber. Uniformity of subsequent etch processes maythen be improved, along with more consistent etching between substrates.

Although the remaining disclosure will routinely identify specificetching processes utilizing the disclosed technology, it will be readilyunderstood that the systems and methods are equally applicable todeposition and cleaning processes as may occur in the describedchambers. Accordingly, the technology should not be considered to be solimited as for use with etching processes or chambers alone. Moreover,although an exemplary chamber is described to provide foundation for thepresent technology, it is to be understood that the present technologycan be applied to virtually any semiconductor processing chamber thatmay allow the single-chamber operations described.

FIG. 1 shows a top plan view of one embodiment of a processing system100 of deposition, etching, baking, and curing chambers according toembodiments. In the figure, a pair of front opening unified pods (FOUPs)102 supply substrates of a variety of sizes that are received by roboticarms 104 and placed into a low pressure holding area 106 before beingplaced into one of the substrate processing chambers 108 a-f, positionedin tandem sections 109 a-c. A second robotic arm 110 may be used totransport the substrate wafers from the holding area 106 to thesubstrate processing chambers 108 a-f and back. Each substrateprocessing chamber 108 a-f, can be outfitted to perform a number ofsubstrate processing operations including the dry etch processesdescribed herein in addition to cyclical layer deposition (CLD), atomiclayer deposition (ALD), chemical vapor deposition (CVD), physical vapordeposition (PVD), etch, pre-clean, degas, orientation, and othersubstrate processes.

The substrate processing chambers 108 a-f may include one or more systemcomponents for depositing, annealing, curing and/or etching a dielectricor metallic film on the substrate wafer. In one configuration, two pairsof the processing chambers, e.g., 108 c-d and 108 e-f, may be used todeposit material on the substrate, and the third pair of processingchambers, e.g., 108 a-b, may be used to etch the deposited material. Inanother configuration, all three pairs of chambers, e.g., 108 a-f, maybe configured to etch a dielectric or metallic film on the substrate.Any one or more of the processes described may be carried out inchamber(s) separated from the fabrication system shown in differentembodiments. It will be appreciated that additional configurations ofdeposition, etching, annealing, and curing chambers for dielectric filmsare contemplated by system 100.

FIG. 2A shows a cross-sectional view of an exemplary process chambersystem 200 with partitioned plasma generation regions within theprocessing chamber. During film etching, e.g., titanium nitride,tantalum nitride, tungsten, copper, cobalt, silicon, polysilicon,silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide,etc., a process gas may be flowed into the first plasma region 215through a gas inlet assembly 205. A remote plasma system (RPS) 201 mayoptionally be included in the system, and may process a first gas whichthen travels through gas inlet assembly 205. The inlet assembly 205 mayinclude two or more distinct gas supply channels where the secondchannel (not shown) may bypass the RPS 201, if included.

A cooling plate 203, faceplate 217, ion suppressor 223, showerhead 225,and a substrate support 265, having a substrate 255 disposed thereon,are shown and may each be included according to embodiments. Thepedestal 265 may have a heat exchange channel through which a heatexchange fluid flows to control the temperature of the substrate, whichmay be operated to heat and/or cool the substrate or wafer duringprocessing operations. The wafer support platter of the pedestal 265,which may comprise aluminum, ceramic, or a combination thereof, may alsobe resistively heated in order to achieve relatively high temperatures,such as from up to or about 100° C. to above or about 600° C., using anembedded resistive heater element.

The faceplate 217 may be pyramidal, conical, or of another similarstructure with a narrow top portion expanding to a wide bottom portion.The faceplate 217 may additionally be flat as shown and include aplurality of through-channels used to distribute process gases. Plasmagenerating gases and/or plasma excited species, depending on use of theRPS 201, may pass through a plurality of holes, shown in FIG. 2B, infaceplate 217 for a more uniform delivery into the first plasma region215.

Exemplary configurations may include having the gas inlet assembly 205open into a gas supply region 258 partitioned from the first plasmaregion 215 by faceplate 217 so that the gases/species flow through theholes in the faceplate 217 into the first plasma region 215. Structuraland operational features may be selected to prevent significant backflowof plasma from the first plasma region 215 back into the supply region258, gas inlet assembly 205, and fluid supply system 210. The faceplate217, or a conductive top portion of the chamber, and showerhead 225 areshown with an insulating ring 220 located between the features, whichallows an AC potential to be applied to the faceplate 217 relative toshowerhead 225 and/or ion suppressor 223. The insulating ring 220 may bepositioned between the faceplate 217 and the showerhead 225 and/or ionsuppressor 223 enabling a capacitively coupled plasma (CCP) to be formedin the first plasma region. A baffle (not shown) may additionally belocated in the first plasma region 215, or otherwise coupled with gasinlet assembly 205, to affect the flow of fluid into the region throughgas inlet assembly 205.

The ion suppressor 223 may comprise a plate or other geometry thatdefines a plurality of apertures throughout the structure that areconfigured to suppress the migration of ionically-charged species out ofthe first plasma region 215 while allowing uncharged neutral or radicalspecies to pass through the ion suppressor 223 into an activated gasdelivery region between the suppressor and the showerhead. Inembodiments, the ion suppressor 223 may comprise a perforated plate witha variety of aperture configurations. These uncharged species mayinclude highly reactive species that are transported with less reactivecarrier gas through the apertures. As noted above, the migration ofionic species through the holes may be reduced, and in some instancescompletely suppressed. Controlling the amount of ionic species passingthrough the ion suppressor 223 may advantageously provide increasedcontrol over the gas mixture brought into contact with the underlyingwafer substrate, which in turn may increase control of the depositionand/or etch characteristics of the gas mixture. For example, adjustmentsin the ion concentration of the gas mixture can significantly alter itsetch selectivity, e.g., SiNx:SiOx etch ratios, Si:SiOx etch ratios, etc.In alternative embodiments in which deposition is performed, it can alsoshift the balance of conformal-to-flowable style depositions fordielectric materials.

The plurality of apertures in the ion suppressor 223 may be configuredto control the passage of the activated gas, i.e., the ionic, radical,and/or neutral species, through the ion suppressor 223. For example, theaspect ratio of the holes, or the hole diameter to length, and/or thegeometry of the holes may be controlled so that the flow ofionically-charged species in the activated gas passing through the ionsuppressor 223 is reduced. The holes in the ion suppressor 223 mayinclude a tapered portion that faces the plasma excitation region 215,and a cylindrical portion that faces the showerhead 225. The cylindricalportion may be shaped and dimensioned to control the flow of ionicspecies passing to the showerhead 225. An adjustable electrical bias mayalso be applied to the ion suppressor 223 as an additional means tocontrol the flow of ionic species through the suppressor.

The ion suppressor 223 may function to reduce or eliminate the amount ofionically charged species traveling from the plasma generation region tothe substrate. Uncharged neutral and radical species may still passthrough the openings in the ion suppressor to react with the substrate.It should be noted that the complete elimination of ionically chargedspecies in the reaction region surrounding the substrate may not beperformed in embodiments. In certain instances, ionic species areintended to reach the substrate in order to perform the etch and/ordeposition process. In these instances, the ion suppressor may help tocontrol the concentration of ionic species in the reaction region at alevel that assists the process.

Showerhead 225 in combination with ion suppressor 223 may allow a plasmapresent in first plasma region 215 to avoid directly exciting gases insubstrate processing region 233, while still allowing excited species totravel from chamber plasma region 215 into substrate processing region233. In this way, the chamber may be configured to prevent the plasmafrom contacting a substrate 255 being etched. This may advantageouslyprotect a variety of intricate structures and films patterned on thesubstrate, which may be damaged, dislocated, or otherwise warped ifdirectly contacted by a generated plasma. Additionally, when plasma isallowed to contact the substrate or approach the substrate level, therate at which oxide species etch may increase. Accordingly, if anexposed region of material is oxide, this material may be furtherprotected by maintaining the plasma remotely from the substrate.

The processing system may further include a power supply 240electrically coupled with the processing chamber to provide electricpower to the faceplate 217, ion suppressor 223, showerhead 225, and/orpedestal 265 to generate a plasma in the first plasma region 215 orprocessing region 233. The power supply may be configured to deliver anadjustable amount of power to the chamber depending on the processperformed. Such a configuration may allow for a tunable plasma to beused in the processes being performed. Unlike a remote plasma unit,which is often presented with on or off functionality, a tunable plasmamay be configured to deliver a specific amount of power to the plasmaregion 215. This in turn may allow development of particular plasmacharacteristics such that precursors may be dissociated in specific waysto enhance the etching profiles produced by these precursors.

A plasma may be ignited either in chamber plasma region 215 aboveshowerhead 225 or substrate processing region 233 below showerhead 225.Plasma may be present in chamber plasma region 215 to produce theradical precursors from an inflow of, for example, a fluorine-containingprecursor or other precursor. An AC voltage typically in the radiofrequency (RF) range may be applied between the conductive top portionof the processing chamber, such as faceplate 217, and showerhead 225and/or ion suppressor 223 to ignite a plasma in chamber plasma region215 during deposition. An RF power supply may generate a high RFfrequency of 13.56 MHz but may also generate other frequencies alone orin combination with the 13.56 MHz frequency.

FIG. 2B shows a detailed view 253 of the features affecting theprocessing gas distribution through faceplate 217. As shown in FIGS. 2Aand 2B, faceplate 217, cooling plate 203, and gas inlet assembly 205intersect to define a gas supply region 258 into which process gases maybe delivered from gas inlet 205. The gases may fill the gas supplyregion 258 and flow to first plasma region 215 through apertures 259 infaceplate 217. The apertures 259 may be configured to direct flow in asubstantially unidirectional manner such that process gases may flowinto processing region 233, but may be partially or fully prevented frombackflow into the gas supply region 258 after traversing the faceplate217.

The gas distribution assemblies such as showerhead 225 for use in theprocessing chamber section 200 may be referred to as dual channelshowerheads (DCSH) and are additionally detailed in the embodimentsdescribed in FIG. 3. The dual channel showerhead may provide for etchingprocesses that allow for separation of etchants outside of theprocessing region 233 to provide limited interaction with chambercomponents and each other prior to being delivered into the processingregion.

The showerhead 225 may comprise an upper plate 214 and a lower plate216. The plates may be coupled with one another to define a volume 218between the plates. The coupling of the plates may be so as to providefirst fluid channels 219 through the upper and lower plates, and secondfluid channels 221 through the lower plate 216. The formed channels maybe configured to provide fluid access from the volume 218 through thelower plate 216 via second fluid channels 221 alone, and the first fluidchannels 219 may be fluidly isolated from the volume 218 between theplates and the second fluid channels 221. The volume 218 may be fluidlyaccessible through a side of the gas distribution assembly 225.

FIG. 3 is a bottom view of a showerhead 325 for use with a processingchamber according to embodiments. Showerhead 325 may correspond with theshowerhead 225 shown in FIG. 2A. Through-holes 365, which show a view offirst fluid channels 219, may have a plurality of shapes andconfigurations in order to control and affect the flow of precursorsthrough the showerhead 225. Small holes 375, which show a view of secondfluid channels 221, may be distributed substantially evenly over thesurface of the showerhead, even amongst the through-holes 365, and mayhelp to provide more even mixing of the precursors as they exit theshowerhead than other configurations.

The chambers discussed previously may be used in performing exemplarymethods including etching methods. Turning to FIG. 4, exemplaryoperations of a method 400 according to embodiments of the presenttechnology are shown. During some or all of the operations of method400, no substrate or some sort of dummy or unprocessed substrate may bepresent in the substrate processing region of a semiconductor processingchamber. The method may include flowing one or more precursors into aremote plasma region at optional operation 405. In some embodiments, theprecursors may be flowed directly into a substrate processing regionwhere a plasma may be ignited locally. In either scenario, the methodmay include striking a plasma to produce plasma effluents, which may beconditioning plasma effluents at operation 410. When formed in a remoteplasma region, the conditioning plasma effluents may be flowed into theprocessing region of the chamber at operation 415. Sidewalls, apedestal, a showerhead, or other chamber components noted previously maybe contacted by the conditioning plasma effluents on interior surfacesthat may define the substrate processing region of the semiconductorprocessing chamber. The methods may then treat the interior chambersurfaces of the semiconductor processing chamber at operation 420.

Method 400 may include additional optional operations in which asubstrate may be processed subsequent the treatment. For example, atoptional operation 425, a substrate may be delivered or transferred tothe substrate processing region of the semiconductor processing chamber.The substrate may have been processed prior to the transfer, and theprocessing may include feature formation, which may include deposition,etching, or other fabrication processes. In an exemplary process, thesubstrate may be characterized by one or more exposed materials on thesubstrate. For example, the substrate may include exposed regions oftitanium nitride, tungsten, silicon oxide, silicon nitride, or othersilicon-containing, nitrogen-containing, oxygen-containing,carbon-containing, or metal containing materials. Method 400 may alsoinclude selectively etching one or more of the materials, such astitanium nitride, at optional operation 430.

The etching operation may be performed in one or more ways, and inembodiments the etching may be performed by a plasma-enhanced dry etchprocess. As will be discussed further below, treating the chamber asdiscussed may facilitate uniformity improvements of the etching when theetchant precursors include a fluorine-containing precursor. For example,the etching process may include flowing a fluorine-containing precursorinto a remote plasma region fluidly coupled with the substrateprocessing region in which the substrate has been positioned. The remoteplasma region may be separated from the substrate processing region withone or more components, such as a showerhead and/or an ion suppressor asdescribed previously. Etching plasma effluents may be produced from thefluorine-containing precursor and delivered to the substrate processingregion through apertures or through-holes of the ion suppressor and/orthe showerhead. The exposed region of titanium nitride may be etchedwith the etching plasma effluents selective to other exposed materialson the substrate.

In some embodiments the etching may be performed without plasmaenhancement. For example, one or more fluorine-containing precursors maybe flowed directly into the substrate processing region. Thefluorine-containing precursors may interact with the exposed region oftitanium nitride, and may etch the titanium nitride selective to otherexposed materials. By performing a selective etch of titanium nitride,maintaining other materials within a device structure may be improved tominimize or prevent loss. For example, in some DRAM structures, tungstenmay be seated in trenches formed in silicon-containing materials, suchas silicon oxide, silicon nitride, or silicon, and one or more linermaterials may be disposed about the trench, such as titanium or tantalumnitride. Processing may include removing the exposed nitride liner whilemaintaining the tungsten.

Conventional processing, including plasma processing may at leastpartially etch the tungsten as well through one or more mechanisms. Forexample, local plasma formation may expose the tungsten to ionic speciesproduced, which may perform a bombardment effect on the tungsten,lowering the selectivity relative to nitride. By producing etchingplasma precursors remotely in some embodiments of the presenttechnology, the ions may be filtered from the plasma effluents by theion suppressor, which may improve the etch selectivity to nitriderelative to tungsten, silicon oxide, or silicon nitride. Because of thebenefits that may additionally be provided by the chamber, a number ofprecursors may be utilized in the present technology. The remote plasmaregion may be located within a distinct module separate from theprocessing chamber, such as an RPS unit, or within a partitioned regionwithin the processing chamber. The separate plasma region may be fluidlycoupled with the substrate processing region by apertures in ashowerhead and/or ion suppressor positioned between the two regions.

In either plasma or non-plasma processing, nitrogen trifluoride may beused as the fluorine-containing precursor utilized in the etching. Othersources of fluorine may be used to augment or replace the nitrogentrifluoride. In general, an etching fluorine-containing precursor may beflowed into the remote plasma region or delivered directly to thesubstrate processing region, and the etching fluorine-containingprecursor may include one or more of atomic fluorine, diatomic fluorine,boron trifluoride, chlorine trifluoride, nitrogen trifluoride, hydrogenfluoride, perfluorinated hydrocarbons, sulfur hexafluoride, chlorinetrifluoride, and xenon hexafluoride. Nitrogen trifluoride may offer abenefit during plasma processes as the precursor may form long-livedradical fluorine in the conditioning plasma effluents and the etchingplasma effluents. Radical fluorine formed from nitrogen trifluorideremains highly reactive even after passing through showerheads and/orion suppression elements described herein.

One or more hydrogen-containing precursors may also be included in theetching precursors, and may be included in plasma and non-plasmaembodiments. For example, diatomic hydrogen, ammonia, or otherhydrogen-containing materials may be included with thefluorine-containing precursor to facilitate the etching. Additionally,oxygen or an oxygen-containing precursor may be flowed with thefluorine-containing precursor to produce etchant species.

In each remote plasma or local plasma described herein, the flows of theprecursors into the remote plasma region may further include one or morerelatively inert gases or carrier gases such as He, N₂, or Ar. The inertgas can be used to improve plasma stability, ease plasma initiation, andimprove process uniformity. Argon may promote the formation of a stableplasma. Process uniformity may be generally increased when helium isincluded. These additives may be included with various embodiments ofthe present technology. Flow rates and ratios of the different gases maybe used to control etch rates and etch selectivity.

As previously discussed, the conditioning plasma may be formed from anoxygen-containing precursor, such as oxygen, ozone,nitrogen-and-oxygen-containing precursors, or other oxygen-containingmaterials. When fluorine-containing precursors are used in etchingoperations including plasma processing, one or more etchant species maybe developed including hydrogen fluoride, and various fluorine andnitrogen-and-fluorine radical materials including radical fluorine.Without intending to limit the present disclosure to any particulartheory, radical fluorine may have one or more competing or limitingeffects on etch rates and selectivity of etching operations relative toother etchant species, such as hydrogen fluoride species, for example.Additionally, radical fluorine may not as readily be withdrawn from aprocessing chamber subsequent etching operations, and may adhere tointerior surfaces of the processing chamber. On subsequent etchingoperations, such as in subsequent cycles or with subsequently processedsubstrates, residual fluorine adhering to the interior surfaces of theprocessing chamber may impact the etching being performed. Because thefluorine will be localized near edge regions of the substrate, theetching may be reduced along edge regions, and may produce reduceduniformity between central regions of the substrate and edge regionsnearer to the chamber sidewalls.

However, when a treatment is performed such as described in relation tomethod 400, the residual fluorine may be removed from the chamber,improving etch uniformity as well as consistency of processingsubstrate-to-substrate. The treatment operations may include anoxygen-containing precursor as previously discussed in order to oxidizethe radical fluorine and desorb the fluorine from the chamber surfaces.By performing the treatments according to embodiments of the presenttechnology, etch uniformity may be improved. For example, an amount oftitanium nitride at an edge region of the substrate and an amount oftitanium nitride at a central region of the substrate may be etched towithin less than or about 10% of one another when treatments areperformed according to the present technology. In some embodiments, anamount of titanium nitride at an edge region of the substrate and anamount of titanium nitride at a central region of the substrate may beetched to within less than or about 8% of each other, less than or about6%, less than or about 5%, less than or about 4%, less than or about 3%,less than or about 2%, less than or about 1%, or may be etchedsubstantially or essentially equally when a treatment is performedaccording to the present technology.

The plasma used during the conditioning operation may be generated usingknown techniques including radio frequency excitations,capacitively-coupled power, inductively coupled power, or otherformation techniques. In some embodiments, the energy may be appliedusing a capacitively-coupled plasma formed within the processing chamberas previously described. The remote plasma source power may be betweenabout 100 watts and about 3000 watts, and may be between about 200 wattsand about 1000 watts, or between about 250 watts and about 500 watts inembodiments. The chamber treatment may also involve a local plasmaexcitation instead of or in addition to the remote plasma excitationaccording to some embodiments. The plasma powers of local plasmas usedto perform treatment operations may involve application of the sameplasma powers as the remote plasmas in embodiments. By maintainingrelatively low plasma power during the conditioning operations, lessdamage may be caused to chamber components, and more controlleddissociation of precursors may be performed.

The conditioning or treatment operations may include one or moreadditional precursors with the oxygen-containing precursor. For example,carrier gases or inert precursors as described previously may beincluded in the precursors used. Additionally, a fluorine-containingprecursor, such as any of the previously-noted precursors, may beincluded in the treatment operations. By including a fluorine-containingprecursor, such as nitrogen trifluoride, for example, the effect of thetreatment operation on the chamber may be tempered. Whenoxygen-containing precursors are used alone, the effect on the chambercomponents may be more pronounced, and may limit the predictability ofsubsequent etching operations. However, when a flow of nitrogentrifluoride or another fluorine-containing precursor is included, acontrolled treatment or conditioning process may be performed thatallows consistent etching substrate-to-substrate, and which mayfacilitate predictability of etch rates, etch amounts, and selectivity.Although additional precursors may also be included, in some embodimentsthe conditioning plasma effluents may be essentially devoid of hydrogen.When hydrogen-containing precursors, such as ammonia, for example, areincluded in the conditioning operations, residual hydrogen-containingspecies may be maintained in the chamber, which may affect theselectivity of subsequently performed etching operations.

Chamber components may also be specifically located within theprocessing chamber during the treatment operations. For example, in someembodiments a pedestal may be raised to a position proximate ashowerhead. By raising the pedestal, conditioning plasma effluentsflowing through a showerhead may be directed more turbulently throughthe chamber increasing the contact with chamber sidewalls in lowerportions of the processing chamber within the substrate processingregion. The raised pedestal may create a more dramatic flow profile ofthe conditioning plasma effluents, which may improve the conditioningoperations. Accordingly, in some embodiments, during the treatment orconditioning operations, a top surface of a puck or pedestal within thesubstrate processing region may be maintained less than or about 10 cmfrom the surface of the showerhead or structure defining the substrateprocessing region from above. In some embodiments the surface of thepedestal may be maintained less than or about 8 cm from the surface ofthe showerhead, less than or about 6 cm from the surface of theshowerhead, less than or about 5 cm from the surface of the showerhead,less than or about 4 cm from the surface of the showerhead, less than orabout 3 cm from the surface of the showerhead, less than or about 2 cmfrom the surface of the showerhead, less than or about 1 cm from thesurface of the showerhead, less than or about 0.5 cm from the surface ofthe showerhead, or less.

By performing processes according to the present technology, titaniumnitride may be selectively etched relative to other exposed materials onthe substrate. The etch selectivity, which may be defined as the rate ofremoval of titanium nitride relative to tungsten, silicon oxide, siliconnitride, or other materials, may be greater than or about 50:1, and maybe greater than or about 100:1, greater than or about 150:1, greaterthan or about 200:1, greater than or about 250:1, greater than or about300:1, greater than or about 500:1, greater than or about 1000:1,greater than or about 2000:1, greater than or about 3000:1, or more.Subsequent the etching operation, which may be performed in one or morecycles, the substrate may be removed from the processing chamber. Anadditional treatment process may then be performed prior to etching anadditional substrate.

The conditioning operations may be performed for time periods of lessthan or about 5 minutes in embodiments, and may be performed for timeperiods of less than or about 4 minutes, less than or about 3 minutes,less than or about 2 minutes, less than or about 1 minute, or less.Other process conditions may impact the performance of the operations aswell. For example, a pressure within the chamber may be maintained belowor about 20 Torr in embodiments. The pressure may be maintained below orabout 15 Torr in embodiments, and may be maintained below or about 10Torr, below or about 5 Torr, below or about 4 Torr, below or about 3Torr, or below or about 2 Torr. The pressure may also be maintainedabove or about 1 Torr, above or about 3 Torr, or between about 1 Torrand about 7 Torr. When pressures are reduced below about 1 Torr, theetch rates may slow or etching may cease completely. Additionally, whenpressures increase above or about 7 Torr, etching may increase indifferent materials reducing selectivity to the titanium nitride.

The temperature of the etching and or conditioning operations may bemaintained above or about 100° C. in embodiments, and may be maintainedabove or about 150° C., above or about 200° C., above or about 250° C.,above or about 300° C., above or about 350° C., above or about 400° C.,above or about 450° C., above or about 500° C., or higher, as well aswithin any ranges defined within these ranges. Fluorides produced fromthe titanium nitride may be characterized by lower volatility attemperatures below or about 100° C. or more, and thus highertemperatures may facilitate removal. Additionally, when temperatures aremaintained above or about 300° C., plasma enhancement may not be usedduring the etching operations. By performing etch processes with chamberconditioning according to embodiments of the present technology,increased uniformity of processing as well as improved stabilitysubstrate-to-substrate may be afforded.

In the preceding description, for the purposes of explanation, numerousdetails have been set forth in order to provide an understanding ofvarious embodiments of the present technology. It will be apparent toone skilled in the art, however, that certain embodiments may bepracticed without some of these details, or with additional details.

Having disclosed several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theembodiments. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent technology. Accordingly, the above description should not betaken as limiting the scope of the technology. Additionally, methods orprocesses may be described as sequential or in steps, but it is to beunderstood that the operations may be performed concurrently, or indifferent orders than listed.

Where a range of values is provided, it is understood that eachintervening value, to the smallest fraction of the unit of the lowerlimit, unless the context clearly dictates otherwise, between the upperand lower limits of that range is also specifically disclosed. Anynarrower range between any stated values or unstated intervening valuesin a stated range and any other stated or intervening value in thatstated range is encompassed. The upper and lower limits of those smallerranges may independently be included or excluded in the range, and eachrange where either, neither, or both limits are included in the smallerranges is also encompassed within the technology, subject to anyspecifically excluded limit in the stated range. Where the stated rangeincludes one or both of the limits, ranges excluding either or both ofthose included limits are also included.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural references unless the context clearly dictatesotherwise. Thus, for example, reference to “a precursor” includes aplurality of such precursors, and reference to “the layer” includesreference to one or more layers and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise(s)”, “comprising”, “contain(s)”, “containing”,“include(s)”, and “including”, when used in this specification and inthe following claims, are intended to specify the presence of statedfeatures, integers, components, or operations, but they do not precludethe presence or addition of one or more other features, integers,components, operations, acts, or groups.

1. An method comprising: forming conditioning plasma effluents of anoxygen-containing precursor in a semiconductor processing chamber;contacting interior surfaces of the semiconductor processing chamberbordering a substrate processing region with the conditioning plasmaeffluents; and treating the interior surfaces of the semiconductorprocessing chamber.
 2. The method of claim 1, further comprising:transferring a substrate into the substrate processing region subsequentthe operation of treating the interior surfaces with the conditioningplasma effluents, wherein the substrate comprises an exposed region oftitanium nitride; flowing a fluorine-containing precursor into a remoteplasma region fluidly coupled with the substrate processing region whileforming a remote plasma in the remote plasma region to produce etchingplasma effluents; and etching the exposed region of titanium nitride byflowing the etching plasma effluents into the substrate processingregion through apertures in a showerhead, wherein the showerhead isdisposed between the remote plasma region and the substrate processingregion.
 3. The method of claim 2, wherein the substrate further includesan exposed region of tungsten, and wherein the etching removes titaniumnitride at a selectivity relative to tungsten of greater than or about100:1.
 4. The method of claim 2, wherein an amount of titanium nitrideat an edge region of the substrate and an amount of titanium nitride ata central region of the substrate are etched to within about 5% of oneanother.
 5. The method of claim 2, further comprising flowing ahydrogen-containing precursor with the fluorine-containing precursor toproduce the etching plasma effluents.
 6. The method of claim 5, whereinthe hydrogen-containing precursor is hydrogen or ammonia.
 7. The methodof claim 2, further comprising flowing an oxygen-containing precursorwith the fluorine-containing precursor to produce the etching plasmaeffluents.
 8. The method of claim 2, wherein a temperature of thesubstrate is maintained between about 200° C. and about 500° C. duringthe etching.
 9. The method of claim 1, wherein the substrate processingregion is essentially devoid of hydrogen during the operation oftreating the interior surfaces of the semiconductor processing chamberwith the conditioning plasma effluents.
 10. The method of claim 1,wherein the conditioning plasma effluents are produced locally in thesubstrate processing region of the semiconductor processing chamber. 11.The method of claim 1, wherein the conditioning plasma effluents areproduced in a remote plasma region and are flowed from the remote plasmaregion into the substrate processing region.
 12. The method of claim 1,wherein a plasma power used to produce the conditioning plasma effluentsis less than or about 500 W.
 13. The method of claim 1, wherein thesubstrate processing region is defined from above by a showerhead, andwherein a pedestal within the substrate processing region is maintainedwithin about 5 cm of the showerhead during the treating.
 14. An methodcomprising: forming conditioning plasma effluents of afluorine-containing precursor and an oxygen-containing precursor in asemiconductor processing chamber; contacting interior surfaces of thesemiconductor processing chamber bordering a substrate processing regionwith the conditioning plasma effluents; and treating the interiorsurfaces of the semiconductor processing chamber.
 15. The method ofclaim 14, further comprising: transferring a substrate into thesubstrate processing region subsequent the operation of treating theinterior surfaces with the conditioning plasma effluents, wherein thesubstrate comprises an exposed region of titanium nitride; flowing afluorine-containing precursor into a remote plasma region fluidlycoupled with the substrate processing region while forming a remoteplasma in the remote plasma region to produce etching plasma effluents;and etching the exposed region of titanium nitride by flowing theetching plasma effluents into the substrate processing region throughapertures in a showerhead, wherein the showerhead is disposed betweenthe remote plasma region and the substrate processing region.
 16. Themethod of claim 15, wherein a pressure within the semiconductorprocessing chamber is maintained between about 1 Torr and about 10 Torr.17. The method of claim 15, wherein a temperature of the substrate ismaintained between about 200° C. and about 500° C.
 18. An methodcomprising: forming conditioning plasma effluents of afluorine-containing precursor and an oxygen-containing precursor in asemiconductor processing chamber; contacting interior surfaces of thesemiconductor processing chamber bordering a substrate processing regionwith the conditioning plasma effluents; treating the interior surfacesof the semiconductor processing chamber; transferring a substrate intothe substrate processing region, wherein the substrate comprises anexposed region of titanium nitride; flowing a fluorine-containingprecursor into the substrate processing region; and etching the exposedregion of titanium nitride by contacting the exposed region of titaniumnitride with the fluorine-containing precursor.
 19. The method of claim18, wherein a temperature of the substrate is maintained between about200° C. and about 500° C. during the etching.
 20. The method of claim18, wherein an amount of titanium nitride at an edge region of thesubstrate and an amount of titanium nitride at a central region of thesubstrate are etched to within about 5% of one another.